Integration of capacitors with carbon-lignin based electrodes in rail vehicles for enhanced energy efficiency

The article presents considerations regarding the possibility of recovering braking energy of a rail vehicle. The energy parameters obtained during acceleration and braking of the loaded railbus were taken as input data. It was found that over 13 kWh of energy was lost irretrievably in the braking resistors. Due to the speed of the discussed process, capacitors with an original design were proposed for energy recovery. For the purposes of this study, electrodes were fabricated using carbon derived from lignin carbonization at two distinct temperatures: 900°C and 1000°C. Based on the electrochemical tests carried out, it was found that the second proposed solution achieves a significantly better power-to-weight ratio – 13 kW/kg.